Final Fantasy 11 is a seasoned MMO with grey in its beard, at this point—not entirely unheard of in the industry (World of Warcraft itself is over two decades old), but absolutely in its veteran years. I mean, this is a game that originally came out on the Playstation 2 as well as PCs.
Still, it's trucking along quite nicely. That's per a Famitsu interview (translated here by Automaton) with Yoji Fujito, the director and producer of FF11.
